Downhole Heating Technology – New Solution for Paraffinic Wells

Paraffin represents one of the main case of failures and production losses which facing the entire oil industry. Prevention of paraffin deposition on the subsurface/surface equipment can be achieved by keeping the paraffin dissolved in crude oil or minimizing the adhesion or aggregation process of wax crystals. The paraffin problems which occur, conduct to gradual reduction of the tubular and pipelines internal diameter, restriction or valves blockages, and reduce the equipment capacity until the production is stop. Problems due to paraffin deposition varies and is different according with each commercial field, sometime the difference is from a well to well which producing from the same reservoir with different consistency. How we shall proceed? Before or after paraffin is field on the equipment? How could be avoid the future paraffin deposition? How long the selected method is proper for well ? The decision represents a combination based on oil's chemical & physical characteristics, well's behavior, method selected for prevention or elimination and combined with economic analysis and field experience. The paraffin inhibition applying is a common practice in OMV Petrom, which cover majority of the production wells. For the special wells, which the paraffin inhibition didn't provided satisfying results (multiple intervention due to paraffin deposition) was selected the Down Hole Heating technology (DHH) which was successfully tested in our company since 2014 thanks according with the yearly New Technology Program. The operating principle consists in heating the fluid volume from tubing using the heating cable which can be installed inside tubing, for NF and ESP wells or outside tubing for SRP or PCP wells. The cable is designed and located at the interval of wax crystallization appearance and heats the fluid to the temperature higher than the wax crystallization point (WAT). Since then, the DHH technology had an upward course, proven by high run life (highest value 2500 days / average 813 days) of the technology at the total 47 wells equipped, until this moment. Based on the successful results, recorded of 64% of old production wells equipped, it was decided to apply the technology at first completion of the new wells (36%), thus ensuring the protection of the new equipment. The paper offers an overview of DHH technology implementation, achievements, benefits and online monitoring of technology implementation starting with 2014 until today. The total impact shown a decreasing of no.of failures with 73,8%, the cost of intervention with 76,5%. The production losses decreased only with 5%, which certifies the fact that the technology helping production maintaining during the exploitation in comparison with production losses due paraffin issues recorded at wells without equipped with DHH technology. During 6 years of down hole heating technology application were developed candidate selection decision tree, monitoring the electrical efficiency, using the adaptability capacity of the technology from one well to another and integrate the temperature parameters in online monitoring system as part of digitalization concept of OMV Petrom, aspects which will be present in this article.

A Potential Approach for Paraffin Control for Wells in South West Trinidad Oilfields Using Wax Inhibitors and Paraffin Solvent

Paraffin deposition in production tubing and flow lines is a phenomenon that affects many oil producers. Once paraffin wax has precipitated there is a tendency to agglomerate peripherally to the production flow path which eventually leads to a sectional decrease in tubing or, even, flow blockage across production zones. The impact of paraffin deposition ranges from wellbore issues, flow assurance challenges to total production impairment. In many mature fields, paraffin remediation can be challenging when deposition occurs in the formation especially in near-wellbore regions of producing wells. Temperature loss at these locations induces wax crystallization and subsequent formation damage. A mitigative approach to paraffin deposition in these areas can typically include the utilization of both paraffin inhibitors and paraffin solvents individually or in combination. However, as it pertains to paraffin remediation downhole, inhibitor placement in the formation or at near-wellbore has proven to be very challenging. This paper reviews the performance of two main chemical applications applied to address downhole wax deposition in a well from a South West Trinidad oilfield. The paper also discusses the strategy behind identifying the chemical type for the application and considerations for the placement of the chemical treatment to impact its intended target based on well data and well infrastructure.

Wax-wetting sponges for oil droplets recovery from frigid waters

Energy-efficient recovery of oil droplets from ice-cold water, such as oil sands tailings, marine, and arctic oil spills, is challenging. In particular, due to paraffin wax crystallization at low temperatures, the crude oil exhibits high viscosity, making it difficult to collect using simple solutions like sponges. Here, we report a wax-wetting sponge designed by conforming to the thermoresponsive microstructure of crude oil droplets. To address paraffin wax crystallization, we designed the sponge by coating a polyester polyurethane substrate with nanosilicon functionalized with paraffin-like octadecyl ligands. The wax-wetting sponge can adsorb oil droplets from wastewater between 5° and 40°C with 90 to 99% removal efficacy for 10 cycles. Also, upon rinsing with heptol, the adsorbed oil is released within seconds. The proposed approach of sponges designed to conform with the temperature-dependent microstructure of the crude oils could enable cold water technologies and improve circular economy metrics in the oil industry.